Rock drill



May 3, E C;l GAR-HN ROCK DRILL Filed May ll, 1935 3 Sheets-Sheet l uw b z hm@ 4 L w kw @w w, wm Q 4,7. MW hw ,a v QQ 1 i #5:@ @.N uw .l MTH www L? QW Qa W I w .mw Wn u KANN w uw e d0 x FN.

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May 3; 1938. E. G. GARTIN ROCK DRILL.

Filed May ll, 1935 5 Shfeets-Sheet 2 J5 y 4 4f? 4l 4f" W L 45 fa? fg ff fi W 'M46 a ad fa Q 5 ,f 14;?, i v i @y F. ,e5 g4? y i? 50 1%? @Awa Mmmm May 3, E' G GAR-TIN 2,1

ROCK DRILL Filed May 1l, 1935 5 Sheets-Sheet, 3

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y fm y V Patented May 3, 1938 UNITED STATES APATENT OFFICE ROCK DRILL Elmer G. Gartin, Claremont, N. H., assignor to Sullivan Machinery Company, a corporation of- Massachusetts Application May 11, 1935, Serial No. 21,025

24 Claims. (Cl. 121-5) This invention relates to rock drills, and more 9, respectively, showing a further embodiment of particularly to improvements in feeding means the invention,

for a hammer rock drill of the mounted drifter Fig. 12 is aperspective view of the feed nut type. shown in Figs. 10 and 11 and showing the revers- An object of this invention is to provide an iming ratchet teeth, 5 proved rock drill feeding means. Another ob- Fig. 13 is a perspective view of the reversible ject is to provide an improved automatic drill drive pawl shown in Fig. 10.l feeding means operated by the hammer piston of In these illustrative constructions, the various the drill hammer motor. A further object is to forms of the improved feeding means are shown provide an improved automatic drill feeding embodied in a hammer rock drill of the mounted 10 means operated by the hammer piston of the drill drifter type generally comprising a guide shell I hammer motor and driven through an element for` slidably supporting a drilling motor generalof the drill steel rotation mechanism. Still anly designated 2, of the pressure uid actuated other object is to provide an improved automatic hammer type. The hammer motor comprises a 15 drill feeding means operated by the rifle bar of cylinder 3 having a piston chamber 4 containing 15 the intermittent ratchet and pawl type rotation a reciprocatory hammer piston 5. The hammer means for the drill steel. Yet another object is piston has a striking bar 6, guided in the front to provide in a feeding means of the above charhead I of the piston chamber, for delivering imacter, improved frictionally controlled reversing pact blows to the shank of a drill steel 8. The o means whereby the direction of feed may be redrill steel shank is supported in a chuck bushing versed at the operators will. A still further ob- 9 fixed within a chuck sleeve I0 rotatably mountject is to provide an improved drill feeding ed in the front chuck housing II suitably secured means wherein a manual feed is combined with to the front end of the motor cylinder. Clutched an automatic feed, together with means for renat I2 to the chuck sleeve is a driver member I3 dering the manua1 and automatic feeding means having Usual driving lugs engageable with lugs 25 selectively operative. These and other objects on the drill steel shank for rotating the drill steel will, however, hereinafter more fully appear. With the chuck sleeve while permitting free re- In the accompanying drawings there are shown CiprOCatOry movement of thev steel shank with for purposes of illustration several forms which respect theretO- AS iS Usual in rock drills of the the invention may assume in practice. type disclosed, means is provided for rotating the 30 1, In these drawings, drill steel 8 as it is percussively actuated by the Fig. 11s aviewin1ongitudina1section ofahamhammer piston 5. comprising a ratchet ring I4 mer rock drill of the mounted drifter type havsuitably fixed within the rear end of the motor ing embodied therein one illustrative form of the Cylinder and haVing internal ratchet teeth l5 improved feeding means, With which usual spring pressed pawls I6, sup- 35 Fig. 2 is an enlarged fragmentary view in 1onported by a rotatable pawl carrier Il, are engitudinm section taken substantiany on une 2-2 eageable. Integral with the pawl carrier is a of Fig. 3, spirally grooved rie bar I8 having sliding inter- Fig. 2a is a detail sectional View taken substanlocking connection with a rifle nut I9 fixed Withtially on line 21-2a of Fig. 2, in the hammer piston 5. As the hammer piston 40 Fig. 3 is a cross sectional view taken on line moves forwardly to deliver a blow to the drill 3 3 of Fig. 2, steel shank, the pawls of the pawl carrier slip Fig. 4 is a detail sectional view taken substanover the teeth of the ratchet ring, permitting tially on line 4-4 of Figs. 2 and 3, free rifle bar rotation While, when the piston Fig. 5 is a view similar to Fig. 2 showing a modimoves rearwardly, the pawls of the pawl carrier 45 fied form of construction, engage the ratchet teeth to hold the rifle bar Fig. 6 is a view similar to Fig. 2 showing a furagainst rotary motion. As a result the piston is ther modified form of construction, rotated during its rearward stroke, and this ro- Fig. 7 is a View similar to Fig. 2 showing still. tary piston motion is transmitted to the drill steel another modified form of construction, 8 through straight grooves 20 formed on the pe- 50 Fig. 8 is a cross sectional view showing a fur riphery of the piston striking bar 6 and slidingly ther embodiment of the invention, interlocked with straight lugs 2I formed on the Fig. 9 is a view in longitudinal section taken chuck nut 22 xed within the chuck sleeve I Il. substantially on line 9-9 of Fig. 8, It is accordingly evident that, as the hammer Figs. 10 and 11 are views similar to Figs. 8 and piston reciprocates, the drill steel 8 is intermit- 55 tently rotated by the hammer piston through the ratchet and pawl mechanism. The rear end of the motor cylinder is closed by a rear head 23, while suitably secured to the rear end of the cylinder and holding the head and ratchet ring in position is a rear head block 24. Mounted in the usual manner in the head block is a throttle valve 25 for controlling the flow of pressure fluid from a suitable source of supply through suitable ports and passages to the motor cylinder to effect reciprocation of the hammer piston, as is well understood by those skilled in the art. Means is provided for supplying a cleansing liquid to the drill steel, comprising a supply chamber 26 formed in the rear head block 24 and `communicating through a passage 21 with a Water tube 28, herein extending longitudinally of the cylinder through axial bores in the rifle bar and hammer piston and terminating at its forward extremity within a chamber 29; and this water tube forms a conduit for supplying cleansing liquid to an axial bore 30 formed in the drill steel 8, all in a Well known manner. The guide shell I is of a standard construction and is provided with longitudinal guideways 3| for receiving lateral guides 32, 32 formed along the sides of the motor cylinder 3, and is provided with a bottom trunnion support 33 adapted to be clamped in a suitable saddle mounting of a suitable support.

Now referring to the improved feeding means shown in Figs. 1 to 4 inclusive, it will be noted that the guide shell I has mounted thereon a feed screw 34 journaled at its front end within a bracket 35 xed to the forward end of the shell, and at its rear end journaled in a bracket 36 secured by rod means 31 to the rearward shell extremity. This screw is held stationary during the automatic feeding operation as hereinafter described, and threadedly engaging the feed screw at 38 is a feed nut 39 rotatably supported by the feed screw and held in position thereon between a shoulder 40 on the head block and the rear face of a sleeve 4I, the latter in turn abutting a depending boss on the motor cylinder. In accordance with this invention, formed integrally with the rie bar I8 is a rearward extension 42, and slidably splined on this extension is a sleeve 43 engaging the adjacent end disc of a multiple disc clutch 44 housed in a spur gear 45. Certain of the clutch discs are connected to the sleeve while others are connected to the spur gear. 'I'his spur gear surrounds the rearward extension 42 of the rifle bar in the manner shown in Fig. 2, and is provided with an axial opening 46 for receiving the water tube 28. Interposed between the flange of the sleeve 43 and a shoulder 41 on the rie bar is a at coiled spring 48 for urging the sleeve 43 rearwardly with respect to the rifie bar extension. Threaded at 49 Within the head block and surrounding the water tube 28 is a plug 50 having a chamber 5I receiving a coiled spring 52, the spring acting between a shoulder on the plug and the rear face of the spur gear 45, and this spring cooperates with the coiled spring 48 in maintaining the disc clutch 44 applied under a load su'icient to effect normal drive but to slip when the drive is overloaded. For adjusting the threaded plug 50 to vary the tension of the coiled spring 52 there is formed integrally with the plug a spur gear 53 with which meshes, as shown in Fig. 4, a spur gear 54 formed integral with a rotatable operating shaft 55. This shaft is rotatably mounted in a bore 56 formed in the head block and has its rearward extremity in the form of a knurled grasping portion 51. When it is desired to adjust the tension of the spring, the operator grasps the portion 51 of the shaft and rotates the gearing 54, 53 in such a manner as to screw the plug 50 inwardly or outwardly as desired. As shown, the spur gear 45 meshes with the teeth of a spur gear 58 journaled on a longitudinal shaft 59 and also meshes with a spur gear 60 (Fig. 4) fixed to a longitudinal shaft 6I suitably journaled within the head and head block. Fixed to the shaft 6I is a spur gear 62 meshing with a spur gear 63 coaxial with the gear 58 and likewise journaled on the shaft 59, the gears 60, 62 constituting a reverse drive. The shaft 59 is mounted for axial movement within its bearings in the head and head block and has formed thereon a spur gear 64 meshing with spur gear teeth 65 formed on the exterior periphery of the feed nut 39. As shown in Fig. 2, formed on the opposite faces of the spur gear 64 are clutch teeth engageable with clutch teeth 66, 61 formed on the adjacent faces of the spur gears 63, 58 respectively. The slidable shaft 59 is provided with an operating handle 68 and has formed on its periphery longitudinally spaced annular grooves 69, 69 and an intermediate locking aperture 10, and a spring pressed plunger 1I carried by the head block is engageable with these grooves and locking aperture for holding the shaft 59 in its opposite positions with the clutch teeth of the gear 64 interlocked with either the clutch teeth 66 or 61 on the spur gears 63 and 58 or for locking the shaft against both axial and rotative movement when the clutch teeth are disconnected, with the gear 64 in its neutral position.

Associated with the automatic feeding means above described is the improved manual feeding means whereby the feed screw 34 may be manually rotated while the feed nut 39 is held against rotation, thereby to effect manual feed of the drill along the shell guideways. During the automatic feeding of the drill the feed screw 34 is held against rotative movement by a spring pressed locking plunger 12 carried by the bracket 36 and engageable with the locking aperture 13 formed on the feed screw, and when it is desired to effect manual feed, this locking plunger is released by grasping the knob 14 formed thereon and lifting the locking pin from the locking aperture, there being formed on the knob 14 a pin 15 engageable with the top surface of the bracket 36 when the locking pin is released for maintaining the locking pin in its released position. Attached to the rearward extremity of the feed screw 34 is a manual operating handle 16.

Now referring to the modifications of the feeding means shown in Figs. 1 to 4 inclusive, it will be observed that in Figs. 5 and 6 the spring clutch loading means, together with the spring tension adjusting means, are somewhat modified, while in Fig. 7 both the spring clutch loading means and the clutch operating means have been somewhat changed. As shown in Fig. 5, the rearward extremity 11 of the rifle bar I8 has mounted thereon a clutch sleeve 18 having a sleeve-like portion 19 housing a coiled spring 80 also surrounding the rifle bar extremity. One end of the spring is fixed to the rifle bar and the other end to the sleeve 18, so that rifle bar rotation is transmitted to the sleeve through the spring. Connectible to the sleeve 18 is a series of clutch discs interleaved with a series of clutch discs carried by a spur gear 8I corresponding to the spur gear 45 of the form of the invention shown in Fig. 2. Arranged in a bore 82 formed in the head block is a plug 83, and interposed between a washer sup- 75 ported on this plug and the rear face of the spur gear 8| is a coiled spring 84, and this spring cooperates with the spring 80 in the loading of the clutch discs. In this instance, a gland plug 85 threaded within the head block provides means for maintaining the packing means 86 for the water tube under compression, and at the same time affords means for adjusting the tension of Vthe spring 84 by moving the plug 83 axially withof the invention shown in Fig. 2. Interposed between the adjustable plug 50 and the spur gear 89 is a coiled spring 90 for pressing the clutch discs against a shoulder 9| formed on the rifle bar to maintain the clutch applied. The plug 50 is adjustable by the same means as that shown in Fig. 4. Inthe modification shown in Fig. 7, the rear extremity 92 of the rifle bar I8 has slidably mounted thereon a spur gear 93 corresponding to the spur gear 45 shown in Fig. 2. Engaging a shoulder 94 formed on the rifle bar, and held against rotation with respect to the latter, is a washer 95, while interposed between this washer and the forward face of the gear 93 is a friction plate 96. Engaging the rear face of the spur gear 93 and reacting against pins 91 secured to the rifle bar extremity 92 and surrounding this extremity is a coiled spring 98 for moving the gear 93 forwardly along the rie bar extremity to press the washer 95 and the inner face of the spur gear in tight frictional engagement with the friction plate 96 for yieldingly connecting the spur gear to the rifle bar extremity. In this instance no adjustment is afforded for the spring 98. The sliding spur gear 64 shown in Fig. 2 is, in Fig. 1, provided with a modified form of operating means and is mounted in a different manner. Rotatably supported within the rear head 23 and the head block 24 is a longitudinally stationary shaft 99 on which the spur gears 58 and 63 are journaled, and this shaft has an axial bore |00. Slidably mounted in this shaft bore is an operating rod I| connected by a screw |02 to the spur gear 64, this screw extending from the rod through a longitudinal slot |03 in the shaft into connection with the spur gear. This rod I0| is provided with operating and locking means similar to those employed for the sliding shaft 59 of the form of the invention shown in Fig. 2.

vOtherwise the forms of the invention shown in Figs. 5, 6 and 'I are generally similar to the form ofthe invention shown in Figs. 1 to 4 inclusive.

The operation of the several forms of the invention thus far described is as follows: When it is desired to effect automatic forward feed of the drilling motor 2 along the shell guideways,

the locking pin 12 is operated to lock the feed screw 34 against rotation. The operator then grasps the handle 68 of the sliding shaft 59 to move the clutch teeth on the gear 64 into interlocking engagement with the clutch teeth on the gear 58 and at the same time interrupts locking engagement by the plunger 1| with the locking aperture and effects its engagement in its hold'- ing position within the groove 69. The throttle valve 25 of the drilling motor is then turned into a position to supply pressure fluid to the motor cylinder to eect reciprocation of the hammer piston 5, and as a result the drill steel 8 is percussively actuated and intermittently rotated. During the reciprocatory and rotary movements of the hammer piston, the rie bar I8 is intermittently rotated, and this intermittent rifle bar rotation is transmitted from the rearward portion 42 of the rifle bar through the spring loaded disc clutch 44, spur gear 45, spur gear 58 and the spur gear 64 meshing with the spur gear teeth 65 formed on the rotatable feed nut 39, and as a result the feed nut is rotated with respect to the feed screw in a direction to effect intermittent forward feed of the drilling motor along the guide shell. When it is desired to effect feeding of the drilling motor in a reverse direction with respect to the guide shell, the operator grasps the handle 68 and moves the sliding shaft 59 into its rearmost position, bringing the clutch teeth on the gear 64 into interlocking engagement with the clutch teeth on the gear 63 while disconnecting the gear 64 from the gear 58. At this time the feed nut 39 is rotated with respect to the feed screw in a direction to effect reverse feed through the rearward projection 42 of the rotatable rifle bar, disc clutch 44, spur gear 45, reverse gearing 60, 62, 63, and the spur gear 64 meshing with the gear teeth 65 of the feed nut 39. The tension of the clutch loading springs 52, 48 may be varied as desired by adjusting the plug 50, thereby to prevent overloading of the rotation mechanism and the consequent stalling of the hammer piston. The forms of the invention shown in Figs. 5, 6 and '1 operate to effect feed in the same general manner as the form of the invention shown in Figs. 1 to 4 inclusive.

Now referring to the illustrative embodiment of the invention shown in Figs. 8 and 9, it will be noted that the rifle bar I8 of the drill steel rotation mechanism has formed integral therewith an eccentric portion or crank |05 with which the bifrcated, yoke-shaped end |06 of an oscillatory lever |01 engages, this lever being pivoted at |09 on a longitudinal pivot pin I |0 secured within the rear head block III of the drilling motor. The lever |01 is mounted for oscillation in transverse planes in a chamber |I2 formed in the head block and is bifurcated at its lower end at II3 and carries a longitudinal pivot pin I I4 on which is pivotally mounted an oscillatory pawl |I5 of the push type. This pawl is of the reversible type having oppositely extending pawl portions IIG and ||1 selectively engageable with the ratchet teeth I I8 formed on the exterior periphery of the feed nut. Slidably guided in bores formed in the head block and engaging the pawl portions II6 and I I1 respectively of the reversing pawl are plungers II9 and |20. The plunger |.I9 is yieldingly held in engagement with the pawl portion ||6 by a coiled spring |2I, while the plunger at its upper end carries a packing |22 forming a piston actuated by pressure fluid for yieldingly holding the plunger |20 in engagement with the pawl portion |I1. Pressure fluid is adapted to be supplied from the throttle valve through a passage |24, under the control of a manually operable valve |25, to a passage |24a leading to the plunger bore at the upper side of the packing |22. The valve |25 is provided with a groove |26 continuously connected with the passage |24a leading to the space above plunger |20 and communicable alternatively with passage |24 and with a vent passage |21, the latter for venting the upper end of the plunger bore when the flow of pressure fluid through passage |24 to the plunger receiving bore is interrupted. When the parts are in the position shown in Fig. 8, the

then active plunger ||9 maintains the pawl portion I I 6 yieldingly in engagement with the ratchet teeth, and as the rifle bar I8 is rotated by the hammer piston during its reciprocation, the lever |01 is oscillated about its pivot to move the pawl to effect rotation of the feed nut to effect retraction of the drilling motor. When it is desired to reverse the motor travel and effect forward feed, pressure fluid is supplied to the plunger bore to act on the packing |22, thereby to force the pawl into the dotted line position shown in Fig. 8 with the pawl portion ||1 engaging the ratchet teeth, and as the lever |01 is oscillated by the rifle bar, the feed nut is rotated in the reverse direction and the drill fed forwardly.

In the illustrative embodiment of the invention shown in Figs. 10 to 13 inclusive, the pawl is of the pull type instead of the push type, as shown in Fig. 8, and in this instance the plunger |29 is pressure fluid actuated under the control of the valve |25 while the plunger |30 is actuated by a coiled spring. Pivotally mounted on the pivot pin ||4 of the oscillatory lever |01 is a reversible pawl |3| of the pull type having oppositely disposed pawl portions |32 and |33 offset in longitudinally spaced relation for engagement with reversely positioned ratchet teeth |34 and |35 formed on the feed nut periphery. When pressure fluid is supplied by the valve |25 to the plunger bore to act on the plunger |29, the pawl is held in the position shown in Fig. 1I) with the pawl portion |32 engaging the ratchet teeth |34, and as the lever |01 is oscillated by the rifle bar during reciprocation of the hammer piston, the feed nut is intermittently rotated by the pulll of the pawl portion |32 upon the ratchet teeth |34. When the bore of the plunger |29 is vented the coiled spring acting on the plunger |30 moves the pawl into the dotted line position shown in Fig. l0 with a pawl portion |33 engaging the ratchet teeth |35, and as the lever |01 is oscillated by the rifle bar, the pawl portion engages with a pulling action the ratchet teeth |35 to rotate the feed nut in the opposite direction.

In the several forms of the invention described, the springs, such as 48, 52, 84, and 98 have not been shown with ball-bearings or other antifriction devices arranged at one end thereof to facilitate spring rotation or rotation relative to said springs, as it is obvious that with abundant lubrication, such devices would not be necessary. It will be evident that the gearing etc. will be thoroughly lubricated in practice, and if it were desired to provide anti-friction devices, this would be obvious and involve no need for more than mechanical skill.

In all of the forms of the invention above described, when it is desired to effect manual feed of the drill, the locking pin 12 may be released from the feed screw, and upon rotation of the feed screw by the manual operating handle 16 the drilling motor may be manually fed forwardly or rearwardly along the shell guideways as desired. In the forms of Figs. 8 and 9 and of Figs. 10 to 13, the appropriate pawl will be rendered effective, depending upon the desired direction of manual feed. Other uses and advantages of the improved feeding means will be clearly apparent to those skilled in the art.

While I have in this application specifically described several forms which my invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration, and that the invention may be modied and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. In a rock drill, the combination with a drilling motor having a cylinder having a rear head member, said cylinder containing a reciprocating hammer piston for percussively actuating a drill steel, and a ratchet and pawl type rotation mechanism for the drill steel and including a rifle bar rotated by the hammer piston, of feeding means for the drilling motor operated by the rotary motion of said rifle bar and embodying reversing means mounted on said drilling motor to move therewith and enclosed within said rear head member for effecting feed of the drilling motor in either of opposite directions while said rifle bar rotates always in the same direction.

2. In a rock drill, the combination with a drilling motor having a reciprocating hammer piston for percussively actuating a drill steel and drill steel rotation mechanism operated by said hammer piston and including a rotary element, of feeding means for the drilling motor including feedmechanism driven by said rotary element of said rotation mechanism and carried within the rear end of said drilling motor, said feed mechanism embodying a spring loaded friction clutch set at a predetermined load and adapted to yield automatically upon overloading of the feeding means.

3. In a rock drill, the combination with a drilling motor having a reciprocating hammer piston for percussively actuating a drill steel and drill steel rotation mechanism operated by said hammer piston, of feeding means for the drilling motor including feed gearing mounted on said drilling motor to move therewith and driven by a rotary element of said rotation mechanism and carried within the rear end of said drilling motor, said drilling motor comprising a rear housing enclosing said feed gearing and said feed gearing embodying reversing means selectively operable to effect feed in either of opposite directions while said rotary element always rotates in the same direction.

4. In a rock drill, the combination with a drilling motor and a guide shell on which the motor is slidably guided, of automatic feeding means operated by the drilling motor for feeding the drilling motor along the guide shell, and means operative when said automatic feeding means is inoperative for manually feeding the drilling motor relative to said shell, said feeding means including a feed screw journaled on said guide shell, a feed nut rotatably mounted and movable with said drilling motor, means for holding said feed screw against rotation, and means for holding said feed nut against rotation, said automatic means being operative to rotate said feed nut when said feed screw is held stationary, and said manual means being operative to rotate said feed screw when said feed nut is held against rotation and disconnected from said automatic means.

5. In a rock drill, the combination with a drilling motor having a cylinder having an end housing, said cylinder containing a reciprocating hammer piston for percussively actuating a drill steel and drill steel rotation means operated by the hammer piston and including a rotatable rifle bar,-of feeding means for the drilling motor operated by the rotary motion of the rifle bar for effecting feed of said drilling motor in either of opposite directions and including a feed driv- 'l5 ing element rotatable with the rifle bar, a rotatable feeding element, and transmission means connecting said feed driving element with said rotatable feeding element and embodying selective reverse gearing enclosed within said end housing and movable directly with the drilling motor for effecting rotation of said feeding element in either of opposite directions while said feed driving element rotates always in the same direction.

6. In a rock drill, the combination with a drilling motor having a reciprocating hammer piston for percussively actuating a drill steel and drill steel rotation means operated by the hammer piston and including a rotatable rifle bar, of feeding means for the drilling motor operated by the rotary motion of the rifle bar and including a feed driving element rotatable with the rifle bar, a rotatable feeding element, and transmission means connecting said feed driving element with said rotatable feeding element and embodying a friction clutch located in the transmission means between the feed driving element and said feeding element and set at a predetermined load for automatically preventing overloading of the rotation means.

'7. In a rock drill, the combination with a drilling motor having a reciprocating hammer piston for percussively actuating a drill steel and drill steel rotation means operated by the hammer piston and including a rotatable rifle bar, of feeding means for the drilling motor operated by the rotary motion of the rifle bar and including a feed driving element rotatable with the rifle bar, a rotatable feeding element, and transmission means connecting said feed driving element with said rotatable feeding element and embodying a friction clutch for connecting said driving element to said feeding element and set under a predetermined load whereby the clutch is adapted to slip when the feeding means is overloaded, thereby to prevent automatically` overloading of the rotation means.

8. In a rock drill, the combination with a drilling motor having a drill steel actuator, of means operated by said drill steel actuator for effecting feed of said drilling motor in either of opposite directions and embodying reversing gearing enclosed within the rear end of and carried directly by said drilling motor to move bodily therewith whereby the direction of feed may be reversed at will.

9. In a rock drill, the combination with a drilling motor comprising a cylinder, having a rear head block and a reciprocating hammer piston contained in said cylinder for percussively actuating a drill steel, of feeding means for the drilling motor operated by said hammer piston for effecting feed of the drilling motor in either of opposite directions including a rilie bar rotated by the hammer piston, a feeding element actuated by said rifle bar, and reversing means enclosed within said rear head block for effecting actuation of said feeding element selectively in opposite directions while said rifle bar rotates always in the same direction.

10. In a rock drill, the combination with a. drilling motor comprising a cylinder having a rear head block and a reciprocating hammer piston contained in said cylinder for percussively actuating a drill steel, of feeding means for the drilling motor for feeding the latter in either of opposite directions including a rotation bar slidingly interlocked with and rotated by said hammer piston, a feeding element, gearing operatively connecting said rotation bar tosaid feeding element and embodying reversing gears mounted on said drilling motor to move bodily therewith and enclosed within said rear head block for effecting rotation of said feeding element selectively in opposite directions while said rotation bar rotates always in the same direction.

11. In a rock drill, the combination with a drilling motor comprising a cylinder having a rear head block and a reciprocating hammer piston contained in said cylinder for percussively actuating a drill steel, of feeding means for the drilling motor including a rotary element actuated by said hammer piston, and feed gearing driven by said rotary element and carried within the rear end of said drilling motor, said feed gearing embodying reversing means enclosed within said rear head block and selectively operable to effect feed in either of opposite directions while said rotary element always rotates in the same direction.

12. In a rock drill, the combination with a drilling motor comprising a cylinder having a rear head block and a reciprocating hammer piston contained in said cylinder for percussively actuating a drill steel, of feeding means for the drilling motor including a rifle bar connected to and rotated by said hammer piston, a feed driving element rotatable with the riiie bar, a rotatable feeding element, and transmission means connecting said feed driving element with said rotatable feeding element and embodying selective reverse gearing mounted on said drilling motor to move bodily therewith and enclosed.

within said rear head block for effecting rotation of said feeding element in either of opposite directions while said feed driving element rotates always in the same direction.

13. In combination, a guide shell providing ak longitudinal guideway, a member to be fed slidably guided on said shell guideway for rectilinear movement therealong, and means forA feeding said member along said guideway including relatively rotatable, threadedly connectedfeed screw and nut elements, said feed screw element extending in parallelism with said guideway, and means movable along said guideway with said member to be fed for effecting intermittent rotation of one of said screw and nut elements relative to the other to effect intermittent feed of said member either forwardly or rearwardly along said shell guideway including a pressurefluid-operated motor having relatively reciprocable cylinder and piston elements and movable along said guideway with said member to be fed and arranged with its cylinder axis extending longitudinally of the feed screw element and shell guideway, and transmission means alslo movable along the guideway with said member to be fed during feeding and actuated by the reciprocating element of said motor for effecting rotation of the rotatable one of said screw and nut elements in either of opposite directions relative to the other thereof, said transmission means including reversible ratchet means operable at will to effect rotation of said rotatable element in either of opposite directions relative to said other element.

14. In a rock drill, the combination with a drilling motor having a reciprocating hammer piston for percussively actuating a drill steel and drill steel rotation means operated by thel hammer piston and including a rotation bar connected to the piston, of feeding means for the drilling motor operated by the rotary motion of said rotation bar and including a feed driving element rotatable with said rotation bar, a rotatable feeding element, and transmission means connecting said driving element with said rotatable feeding element and embodying a spring loaded friction clutch located in the transmission means between the feed driving element and said feeding element and set at a predetermined load for automatically preventing overloading of the rotation means, said clutch adapted to slip automatically when the feeding means is overloaded.

15. In a rock drill, the combination with a drilling motor having a drill steel actuator and drill steel rotation means driven by said drill steel actuator, of means operated by an element of said steel rotation means for automatically feeding the drilling motor and embodying a feed driving mechanism carried within the rearward end of said drilling motor, said feed driving mechanism including an eccentric operated by said rotation element and an oscillatory element actuated by said eccentric.

16. In a rock drill, the combination with a drilling motor having a drill steel actuator and drill steel rotation means driven by said drill steel actuator, of means operated by an element of said steel rotation means for automatically feeding the drilling motor and embodying a feed driving mechanism carried within the rearward end of said drilling motor, said feed driving mechanism including an eccentric operated by said rotation element, an oscillatory element actuated by said eccentric, a pawl actuated by said oscillatory element and a ratchet engaged by said pawl.

17. In a rock drill, the combination with a drilling motor having a drill steel actuator and drill steel rotation means driven by said drill steel actuator, of means operated by an element of said steel rotation means for automatically feeding the drilling motor in either of opposite directions and embodying a feed driving mechanism carried within the rearward end of said drilling motor, said feed driving mechanism including an eccentric operated by said rotation element, an oscillatory element actuated by said eccentric and a reversible ratchet and pawl device actuated by said oscillatory element.

18. In combination, a guide shell providing a longitudinal guideway, a member to be fed slidably guided on said shell guideway for rectilinear movement therealong, a feed screw supported by said shell in parallelism with said guideway and fixed against rotation with respect to said shell, a feed nut journaled in said member to be fed and threadedly engaging said feed screw, and means carried by said member to be fed for effecting intermittent rotation of said feed nut to effect intermittent feed of said member either forwardly or rearwardly along said shell guideway including a motor cylinder on said member to be fed and arranged with its bore in parallelism with the feed screw and shell guideway, a pressure fluid actuated piston reciprocable in said cylinder bore, and means actuated by said piston for effecting rotation of said feed nut relative to said feed screw, said feed nut rotating means embodying reversible ratchet means operable at will for effecting rotation of said feed nut in either of opposite directions relative to said screw.

19. In combination, a guide shell providing a longitudinal guideway, a member to be fed slidably guided on said shell guideway for rectilinear movement therealong, a feed screw supported by said shell in parallelism with said guideway and.

fixed against rotation with respect to said shell, a feed nut journaled in said member to be fed and threadedly engaging said feed screw, and means carried by said member to be fed for effecting intermittent rotation of said feed nut to effect intermittent feed of said member either forwardly or rearwardly alang said shell guideway including a motor cylinder supported by said member to be fed and arranged with its bore in parallelism with the feed screw and shell guideway, a pressure fluid actuated piston reciprocable in said cylinder bore, and means actuated by said piston for effecting rotation of said feed nut relative to said feed screw, said feed nut rotating means embodying means for effecting feed nut rotation in either of opposite directions relative to said screw and including ratchet and pawl reversing mechanism operable at will to effect reversal of feed nut rotation.

20. In combination, a guide shell providing a longitudinal guideway, a member to be fed slidably guided on said shell guideway for rectilinear movement therealong, a feed screw supported by said shell in parallelism with said guideway and xed against rotation with respect to said shell, a feed nut journaled in said member to be fed and threadedly engaging said feed screw, and means carried by said member to be fed for effecting intermittent rotation of said feed nut to effect intermittent feed of said member either forwardly or rearwardly along said shell guideway including a motor cylinder supported by said member to be fed and arranged with its bore in parallelism with the feed screw and shell guideway, a pressure fluid actuated piston reciprocable in said cylinder bore, and means actuated by said piston for effecting rotation of said feed nut relative to said screw including a rifle bar actuated by said piston, said feed nut rotating means embodying reversible ratchet means operable at will for effecting feed nut rotation in either of opposite directions relative to said feed screw.

21. In combination, a guide shell providing a longitudinal guideway, a member to be fed slidably guided on said shell guideway for rectilinear movement therealong, a feed screw supported by said shell in parallelism with said guideway and fixed against rotation with respect to said shell, a feed nut journaled in said member to be fed and threadedly engaging said feed screw, and means carried by said member to be fed for effecting rotation of said feed nut to effect feed of said member either forwardly or rearwardly along said shell guideway including a motor cylinder supported by said member to be fed and arranged with its bore in parallelism with the feed screw and shell guideway, a pressure fluid actuated piston reciprocable in said cylinder bore, and means actuated by said piston for effecting rotation of said feed nut relative to said screw including a rie bar actuated by said piston, said feed nut rotating means embodying means for effecting feed nut rotation in either of opposite directions relative to said feed screw and including reversible ratchet and pawl means cooperating with said rifle bar.

22. In combination, a guide shell providing a longitudinal guideway, a member to be fed slidably guided on said shell guideway for rectilinear movement therealong, a feed screw supported by said shell in parallelism with said guideway and fixed against rotation with respect to said shell, a feed nut journaled in said member to be fed and threadedly engaging said feed screw, and

means carried by said member to be fed for effecting rotation of said feed nut to effect feed of said member either forwardly or rearwardly along said shell guideway including a motor cylinder supported by said member to be fed and arranged with its bore in parallelism with the feed screw and shell guideway, a pressure fluid actuated piston reciprocable in said cylinder bore, and means actuated by said piston for effecting rotation of said feed nut relative to said screw including a rifle bar actuated by said piston, said feed nut rotating means embodying means for effecting feed nut rotation in either of opposite directions relative to said feed screw and including reversible ratchet and pawl means cooperating with said rifle bar and means for reversing said ratchet and pawl means while said piston continuously reciprocates.

23. In combination, a guide shell providing a longitudinal guideway, a rock drill guided on said shell guideway for rectilinear movement therealong, a non-rotatable feed screw supported by said guide shell and arranged parallel with the shell guideway, a rotatable feed nut journaled in a part of said drill and threadedly engaging said feed screw, and means movable with the rock drill and arranged at the rearward end of the latter for rotating said feed nut in either of opposite directions relative to said feed screw to effect feed of the rock drill either forwardly or rearwardly along the shell guideway, said means including a rotatable rifle bar, reversible ratchet and pawl means connected to said rifle bar, and means operable at will for reversing said ratchet and pawl means while said rifle bar rotates.

24. In combination, a guide shell providing a longitudinal guideway, a member to be fed guided on said shell guideway for rectilinear movement therealong, a non-rotatable feed screw supported by said guide shell and arranged parallel to said shell guideway, a rotatable feed nut journaled in said member to be fed and threadedly engaging said feed screw, and means movable with said member to be fed for rotating said feed nut selectively in opposite directions to effect feed of the members to be fed in opposite directions, including relatively rotatable screw and nut elements disposed with their axes parallel to the feed screw axis, a motor having its piston coaxial with said elements and reciprocable to effect their relative rotation, ratchet and pawl means coacting with one of said elements, and ratchet and pawl means between said elements and said feed nut.

EIM/[ER G. GARTIN.

.E CERTIFICATE 0F CORRECTION.

Patenb No. 2,115,911. may 5, 1958.

RLMRR C. CARTIN.

It is hereby certified that error appears in the printed speoieationk of the above numbered patent requiring oorreotionas'followss Page 7 second column, line 18, Claim 2h., for Jthe word "members" read member; and after "directions" strike out the comma; and that the said Letters Patent should '1e read with this Correction therein that the same may 'conform to the record Nr-of the, Case in the Patent Office.

signed and sealed this '20th day of september, A. D. 1958.

` Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

